The present disclosure relates to a method for active hybridization with a separate denaturation function.
Microarrays are known as modern molecular-biology test systems. They allow the parallel analysis of several thousand single detections in a small amount of biological sample material. Consequently, various forms of microarrays have been established, which are classified according to the nature of their interactions. These include, firstly, nucleic acid-based microarrays, which are used, for example, to detect DNA, mRNA or rRNA of particular genes of organisms. For this purpose, cDNA, oligonucleotides or fragments of PCR products which are complementary to the mRNA are printed on support materials (“spotted microarrays”). In the case of the “oligonucleotide microarrays”, synthetically produced oligonucleotides are applied to, for example, glass supports. The oligonucleotides acting as probes generate, on the supports, the greatest possible density of information on a very small space in a manner similar to a computer chip, and so microarrays are also readily referred to as “gene chips” or “biochips”.
Further known embodiments are protein arrays, which detect, for example, antigen-antibody, enzyme-substrate, receptor-protein or other protein-protein interactions. It is also possible to detect and quantify binding of nucleic acids to proteins.
When using microarrays in microbiology, the biomolecules from a sample which is, in general, processed and pretreated are applied to the microarray, and, on the individual sites (“spots”) of the microarray, specific binding reactions occur, which consequently provide information about the presence of particular molecules, for example DNA fragments, in the sample. A prerequisite for this binding reaction is the presence of the DNA or RNA as single strands, and so a prior denaturation step is imperative. In the case of generally increasing automation, there is a multiplicity of approaches for performing very many individual steps of the analysis within one device unit in order to thus save time and costs. This includes the use of micropumps, by means of which the extremely small sample volumes are transported within the device units; see in this regard, for example, US 2004/0141856A1.
The actual binding procedure or the hybridization to the probes of the microarray can in turn occupy two or more hours, since the movement of the particles is in accordance with Brownian motion and therefore takes place very slowly. Also, as a result, only some of the target molecules present in the sample reach the respective capture structure, i.e., the probes.